Known in the art are electrodynamic transducers (Polytechnical Dictionary, Moscow, 1977, p. 557) used, for example, in electrodynamic microphones and loudspeakers. The known transducers have a coil, a magnet with a magnetic circuit having an external and internal parts with respect to the coil so as to provide a magnetic gap in which the coil moves thus intersecting the magnetic lines of force at right angles. The known electromagnetic transducers feature a low efficiency, rather a complex design of the magnetic system and considerable weight and overall dimensions. Furthermore, these transducers have low internal resistance, therefore, in some cases they require use of a step-up transformer.
The development of modern acoustical and measuring equipment requires the use of electrodynamic transducers having a simple design, high efficiency and a higher internal resistance eliminating distortion of the signals due to the use of step-up or step-down transformers.
The Faraday experiment was used by the inventor for solving the problem. However, the Faraday instrument consisting of a coil, a magnet and a galvanometer in its original form could not be used as a transducer suitable for practical application due to low efficiency, incomplete utilization of the magnetic field of the magnet and a high noise level due to the action of external magnetic fields.
The known electrodynamic transducers with a movable coil were used as a basis for making pickup heads such as the head "SL 15 Q" of the "Ortophon" company (Funk-Techu, 1974, 29, No. p.p. 201-204).
The head "SL 15 Q" has a magnet with a magnetic circuit providing a magnetic gap, in which are located movable coils mechanically coupled to a stylus holder and a stylus and having flexible leads of a thin wire from the stylus holder subject to vibration. The produced e.m.f. of 0.016 mV/cm/sec is fed through a special cable to a step-up transformer where it is increased to 1.5 mV/cm/sec.
The use of a step-up transformer complicates the construction of the head and results in distortion of the electric signal and in a low efficiency. The magnetic circuit producing the magnetic flux whose lines of force from the unlike magnetic poles are closed through the magnetic gap has considerable weight and overall dimensions. A small number of turns of the coil does not allow one to obtain sufficiently high internal resistance for matching with the amplifier input and to provide high sensitivity of the head. The movable coil has unreliable thin leads subject to mechanical vibration. Furthermore, the head is sensitive to external magnetic fields.
The known electrodynamic transducers with a movable coil are used for making microphones of various types and for different applications (cf. M. M. Efrussi "Microphones and their Application", Moscow, "Energia" Publishers, 1974). The electrodynamic microphones have a magnet with a magnetic circuit for producing a magnetic gap, in which a movable coil is placed, said coil being secured to a diaphragm and having leads to be connected to an external electrical circuit.
Owing to the fact that the magnet of the magnetic circuit produces a magnetic flux whose lines of force from the unlike magnetic poles are closed through the magnetic gap it has a complex configuration or consists of several components, features a considerable weight and a complicated mechanical construction. In spite of a considerable mass of the magnetic system, the microphone is subjected to the effect of magnetic fields. The low number of turns in the coil does not allow one to obtain sufficiently high internal resistance. The presence of a movable coil and thin leads liable to oscillations reduces the reliability of the electrical circuit.
An object of the present invention is to increase the efficiency of an electrodynamic transducer.
Another object of the invention is to reduce the weight and overall dimensions of the electrodynamic transducer.
Still another object is to simplify the technological process of making the transducer.
Yet another object is to increase the noise immunity of the transducer from external magnetic fields.
Another object of the invention is to increase the operational reliability of the transducer.
One more object is to increase the efficiency of a pickup head.
Another object is to reduce the weight and overall dimensions of the pickup head.
Still another object is to increase the sensitivity of the pickup head.
An object of the invention is to increase the internal resistance of the pickup head.
Another object of the invention is to increase the reliability of the electrical circuit of the pickup head.
Another object of the invention is to reduce the sensitivity of the pickup head to the effect of external magnetic fields.
Still another object is to reduce the weight and overall dimensions of a microphone.
Yet another object is to simplify the technological process of making the microphone.
The next object is to increase the internal resistance of the microphone.
The other object of the invention is to increase the reliability of the electrical circuit of the microphone.
The essence of the invention consists in that in an electrodynamic transducer converting mechanical oscillations into electric signals and vice versa including a coil with a pair of sections wound in opposite directions, according to the invention, a magnet mechanically coupled to an actuator, is located within the coil with a possibility of longitudinal movement, the unlike magnetic poles being located in the different sections of the coil.
These and other objects are attained due to the fact that in an electrodynamic transducer converting mechanical oscillations into electric signals and vice versa comprising a coil with a pair of sections wound in opposite directions; according to the invention, a magnet mechanically coupled to an actuator is arranged inside the coil and is capable of moving in a longitudinal direction, the unlike poles of said magnet being located in the different sections of said coil.
The objects are also attained due to the fact that in the electrodynamic transducer comprising a coil and a magnet with a magnetic circuit, according to the invention, the coil has a pair of sections wound in opposite directions; the sections are encompassed by a hollow magnetic circuit; a magnet capable of moving in a longitudinal direction is placed inside said coil; the unlike magnetic poles are located in the different sections of the coil.
It is required that the coil has n pairs of sections and the magnet is made of separate parts, in which case the like poles of two adjacent pairs of the magnet are located opposite to each other and occupy the area of one section of the coil.
The above objects are also attained due to the fact that in a stereophonic pickup head, wherein each playback channel includes one transducer converting mechanical oscillations into electric mechanically coupled to a stylus holder and a stylus, according to the invention, the transducer is an electrodynamic transducer comprising a coil with a pair of sections wound in different directions; said coil accommodates a magnet capable of moving in a longitudinal direction and mechanically coupled to said stylus holder, the like poles of said magnet being located in the different sections of said coil.
One embodiment of the present invention includes a stereophonic pickup head comprising in each playback channel one electrodynamic transducer converting mechanical oscillations into electric signals and mechanically coupled to a stylus holder and a stylus, which has a coil with a pair of sections wound in different directions, a hollow magnetic circuit encompassing the coil, and a magnet placed inside the coil with a possibility of longitudinal displacement; the magnet is mechanically coupled to the stylus holder, the unlike poles of the magnet being arranged in the different sections of the coil.
Another embodiment of the invention consists in that it provides a stereophonic pickup head comprising in each playback channel one electrodynamic transducer converting mechanical oscillations into electric signals having a coil with n pairs of sections wound in opposite directions and mechanically coupled to a stylus holder and a magnet made of separate parts, in which case the like poles of the two adjacent parts of the magnet are arranged in opposition to each other and are located in the area of one section of the coil.
Still another embodiment of the invention consists in that it provides a stereophonic pickup head comprising in each playback channel one electrodynamic transducer converting mechanical oscillations into electric signals mechanically coupled to a stylus holder and a stylus and having a coil with n pairs of sections wound in opposite directions, a hollow magnetic circuit encompassing the coil, and a magnet made of separate parts, the like poles of the two adjacent parts of the magnet being arranged in opposition to each other and located in the area of the same section of the coil.
The magnets of each electrodynamic transducer of the stereophonic pickup head can be mounted directly on the stylus holder in the planes intersecting at an angle .alpha. equal to the standard recording angle.
It is expedient that in the stereophonic pickup head the magnets of each electrodynamic transducer are arranged at both sides along the length of the stylus pickup from its fixing point.
It is also possible that the magnets of each electrodynamic transducer of the stereophonic pickup head are removed from the stylus pickup through a certain distance and are connected thereto through flexible rods.
In order to improve the quality of reproduction of the recording, each playback channel of the stereophonic pickup head should be provided with an additional transducer whose magnets together with their rods are located in planes intersecting at an angle .alpha. equal to the standard recording angle, in which case in each playback channel all the transducers are located at both sides from the longitudinal axis of the stylus holder.
It is expedient that in the stereophonic pickup head the rods are made in the form of a flat band made of a resilient material and twisted along its length.
In order to simplify the technology, the rods are preferably secured on the stylus holder by means of a clamp ring.
The object of the invention is also attained due to the fact that in the monophonic pickup head comprising one transducer for converting mechanical oscillations into electric signals mechanically coupled to a stylus holder and a stylus, according to the invention, the electrodynamic transducer has a coil with one pair of sections wound in different directions accommodating a magnet capable of moving in a longitudinal direction, the unlike poles of said magnet being located in the different sections of the coil.
The invention also includes a monophonic pickup head comprising an electrodynamic transducer converting mechanical oscillations into electric signals mechanically coupled to a stylus holder and a stylus, which has a coil with a pair of sections wound in different directions, a hollow magnetic yoke encompassing the coil and a magnet placed inside the coil with a possibility of longitudinal displacement, in which case the unlike poles of the magnet are located in the different coil sections.
Another embodiment of the invention consists in that it provides a monophonic pickup head comprising an electrodynamic transducer converting mechanical oscillations into electric signals mechanically coupled to a stylus holder and a stylus, a coil with n pairs of sections wound in different directions, and a magnet made of separate parts, in which case the like poles of the two adjacent parts of the magnet are positioned in opposition to each other and are in the area of the same coil section.
In accordance with one embodiment of the invention, the monophonic pickup head comprises an electrodynamic transducer converting mechanical oscillations into electric signals mechanically coupled to a stylus holder and a stylus and having a coil with n pairs of sections wound in opposite directions, a hollow magnetic circuit encompassing the coil, and a magnet made of separate parts, in which case the like poles of the two adjacent parts of the magnet are arranged in opposition and are located in the area of the same coil section.
The object of the present invention is also attained due to the fact that in an electrodynamic microphone comprising a transducer converting mechanical oscillations into electric signals and mechanically coupled to a diaphragm, according to the invention, the transducer is an electrodynamic transducer containing a coil with a pair of sections wound in different directions. Mounted inside the coil is a magnet capable of moving in a longitudinal direction, the unlike poles of the magnet being located in the different coil sections.
According to one embodiment of the invention, the latter includes an electrodynamic microphone comprising an electrodynamic transducer converting mechanical oscillations into electric signals mechanically coupled to a diaphragm. According to the invention, the transducer has a coil with a pair of sections wound in opposite directions, a hollow magnetic yoke encompassing the coil and a magnet placed inside the coil with a possibility of longitudinal displacement, the unlike poles of the magnet being located in different coil sections.
Another embodiment of the invention consists in that the electrodynamic microphone comprises an electrodynamic transducer converting mechanical oscillations into electric signals and mechanically connected to a diaphragm. According to the invention, the transducer comprises a coil with n pairs of sections wound in opposite directions and a magnet made of separate parts, the like poles of the two adjacent parts of the magnet being positioned in opposition to each other and being located in the area of the same coil section.
According to another embodiment of the invention the microphone comprises an electrodynamic transducer converting mechanical oscillations into electric signals and mechanically coupled to a diaphragm. According to the invention, the transducer has a coil with n pairs of sections wound in opposite directions, a hollow magnetic circuit encompassing the coil, and a magnet made of separate parts, the like poles of the two adjacent parts of the magnet being arranged in opposition to each other and located in the area of the same coil section.
The proposed invention makes it possible to increase the efficiency of an electrodynamic transducer, to reduce its weight, to simplify its manufacturing technology, to increase its reliability and magnetic noise immunity. The use of the proposed electrodynamic transducer in pickup and microphone heads makes it possible to increase their efficiency and magnetic noise immunity, to reduce their weight and overall dimensions while increasing the sensitivity of these heads, and to simplify the manufacturing technology of microphones.